Conventional paper bails for printers consist of a paper bail shaft on which are rotatably supported a plurality of individual paper bails. These bails are in the form of rollers which are slidable along the axis of the paper bail shaft and are applied with pressure against the platen so as to guidably advance the paper after it has been printed.
The pressure of the paper bail rollers against the platen is produced with springs that are in engagement with a holder that can move the paper bail shaft between operative and inoperative positions.
A number of problems are evident in conventional paper bails and these become accentuated in high speed printers, particularly at the end of a page of printing.
More particularly, the bail shaft is relatively long and not especially rigid so that pressure variation of the bails against the platen can be substantial which can lead to incomplete pressing of the paper against the platen and consequent misfeed of the paper.
Additionally, at the bottom of a page, when the paper has been released from the friction rollers which hold the paper against the platen, the paper is now free to be dislodged and is only held against the platen by the paper bail rollers. As a consequence, the last few lines of printing on the paper may become irregular and frequently it is noted that the last lines of printing are skewed at an angle.
Additionally, a further requirement currently made upon printers is to have so-called "multi-strike" capability. This requires that different characters be imprinted at the same place offset vertically a plurality of times. This requires careful registration of the print element and the printed character in order to prevent offset overlap of the printed character. As previously explained, at the end of the paper when the paper is only held by the rollers of the paper bail against the platen, the paper can shift leading to offset of the printed multistruck character.
A deficiency of the known construction in which the paper bail rollers are capable only of sliding movement on the paper bail shaft is that it is necessary for an operator to raise the paper bail shaft every time it is necessary to insert a sheet of paper under the paper bail.